使用Python matplotlib-venn查找交叉值

Question

我一直在使用matplotlib-venn生成3组的维恩图。如下所示。

我想问一下如何找到这些集合的相交值。例如，与集合A和集合B相交的384个值是多少？与集合A，集合B和集合C相交的144个值是什么？非常值得。

谢谢。

罗德里戈

Answer 1

假设您正在使用内置的Python set对象，获取两个集合之间的交集非常简单。见这个例子：

>>> a = set(range(30))
>>> b = set(range(25,50))
>>> a.intersection(b)
set([25, 26, 27, 28, 29])

Answer 2

我知道这是一个老问题，但我最近也遇到了类似的问题。为了未来的访问者，我在这里分享我的解决方案。下面的代码提供了一个解决方案，用于识别维恩图的每个部分的成员资格。仅交叉点是不够的，您还必须减去不需要的集合。

def get_venn_sections(sets):
    """
    Given a list of sets, return a new list of sets with all the possible
    mutually exclusive overlapping combinations of those sets.  Another way
    to think of this is the mutually exclusive sections of a venn diagram
    of the sets.  If the original list has N sets, the returned list will
    have (2**N)-1 sets.

    Parameters
    ----------
    sets : list of set

    Returns
    -------
    combinations : list of tuple
        tag : str
            Binary string representing which sets are included / excluded in
            the combination.
        set : set
            The set formed by the overlapping input sets.
    """
    num_combinations = 2 ** len(sets)
    bit_flags = [2 ** n for n in range(len(sets))]
    flags_zip_sets = [z for z in zip(bit_flags, sets)]

    combo_sets = []
    for bits in range(num_combinations - 1, 0, -1):
        include_sets = [s for flag, s in flags_zip_sets if bits & flag]
        exclude_sets = [s for flag, s in flags_zip_sets if not bits & flag]
        combo = set.intersection(*include_sets)
        combo = set.difference(combo, *exclude_sets)
        tag = ''.join([str(int((bits & flag) > 0)) for flag in bit_flags])
        combo_sets.append((tag, combo))
    return combo_sets